Low-cost label-free biosensors using photonic crystals embedded between crossed polarizers

Nazirizadeh, Yousef; Bog, Uwe; Sekula, S.T.; Mappes, Timo; Lemmer, Uli; Gerken, Martina

doi:10.1364/oe.18.019120

Cited by 70 publications

(47 citation statements)

References 15 publications

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“…Via the USB interface the LED and the camera are controlled with a computer as well as real-time data processing can be realized for noise minimization during the protein detection. Aligning the guided-mode resonance of the PCS to the falling edge of a colored LED the resonance shift due to binding kinetics of the protein results in an intensity reduction in the transmitted light [13]. This intensity change can be recorded with the camera by continuously taking pictures of the sensor surface during the protein binding process.…”

Section: Protein Detection With Fluid Cellmentioning

confidence: 99%

Imaging label-free biosensor with microfluidic system

et al. 2015

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We present a microfluidic system suitable for parallel label-free detection of several biomarkers utilizing a compact imaging measurement system. The microfluidic system contains a filter unit to separate the plasma from human blood and a functionalized, photonic crystal slab sensor chip. The nanostructure of the photonic crystal slab sensor chip is fabricated by nanoimprint lithography of a period grating surface into a photoresist and subsequent deposition of a TiO 2 layer. Photonic crystal slabs are slab waveguides supporting quasi-guided modes coupling to far-field radiation, which are sensitive to refractive index changes due to biomarker binding on the functionalized surface. In our imaging read-out system the resulting resonance shift of the quasi-guided mode in the transmission spectrum is converted into an intensity change detectable with a simple camera. By continuously taking photographs of the sensor surface local intensity changes are observed revealing the binding kinetics of the biomarker to its specific target. Data from two distinct measurement fields are used for evaluation. For testing the sensor chip, 1 µM biotin as well as 1 µM recombinant human CD40 ligand wereimmobilized in spotsvia amin coupling to the sensor surface. Each binding experiment was performed with 250 nM streptavidin and 90 nM CD40 ligand antibody dissolved in phosphate buffered saline. In the next test series, a functionalized sensor chip was bonded onto a 15 mm x 15 mm opening of the 75 mm x 25 mm x 2 mm microfluidic system. We demonstrate the functionality of the microfluidic system for filtering human blood such that only blood plasma was transported to the sensor chip. The results of first binding experiments in buffer with this test chip will be presented.

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Section: Protein Detection With Fluid Cellmentioning

confidence: 99%

Imaging label-free biosensor with microfluidic system

et al. 2015

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“…A further property of the GMR, which is affected by a refractive index change, is its quality factor, which is inversely proportional to the line width of the resonance. Using a spectrometer, today GMRs are used in various biological applications ranging from biosensors [13][14][15] to cell analysis [16]. However, in a visual transmission experiment with a white light source, as used in many light microscopes, the GMRs do not induce any specific color or intensity changes.…”

Section: Photonic Crystal Slabs As the Specimen Holdermentioning

confidence: 99%

Photonic crystal slabs for surface contrast enhancement in microscopy of transparent objects

et al. 2012

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Abstract:In optical microscopy the contrast of transparent objects achieved with conventional methods is often not satisfactory, for example for the automated recognition of cells. In this paper we present a nanooptical label-free approach for contrast enhancement based on photonic crystal slabs (PCS) as the specimen holder. Quasi-guided modes inside these structures cause an intrinsic color of the PCS, which strongly depends on the wavelength and the quality factor of the optical mode. Objects on the surface of the PCS experience a significant color and intensity contrast enhancement, as they change properties of the optical modes.

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“…The position of resonance's central wavelength depends on the resulting refractive index change and is used as a measure of the binding. The central wavelength is determined either via a spectrometer [7,8] or using a spectrally limited light source, which is matched to a resonance in order to transform the spectral shift into an inexpensive photometric experiment [9]. The detection limit of such measurements is a function of the optical detection method, the line width of the resonance, and the PCS's sensitivity defined as the resonance wavelength shift Δλ divided by the refractive index change Δn [10].…”

Section: Introductionmentioning

confidence: 99%

Sensitivity optimization of injection-molded photonic crystal slabs for biosensing applications

Nazirizadeh¹,

Oertzen²,

Plewa³

et al. 2013

Opt. Mater. Express

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For label-free assays employing photonic crystal slabs (PCSs), the sensitivity is one of the most important properties influencing the detection limit. We investigate the bulk sensitivity and the surface sensitivity of 24 different PCSs fabricated by injection molding of PMMA and subsequent sputtering of a Ta 2 O 5 high-index layer. The duty cycle of the linear grating is varied in steps of 0.1 between 0.2 and 0.7. Four different Ta 2 O 5 layer thicknesses (89 nm, 99 nm, 189 nm, 301 nm) are deposited. Both bulk and surface sensitivity are optimal for a Ta 2 O 5 layer thickness of 99 nm. The maximum bulk sensitivity of 138 nm/RIU is achieved for a duty cycle of 0.7, while the maximum surface sensitivity of 47 nm/RIU is obtained for a duty cycle of 0.5. Good agreement between experimental results and finite-difference time-domain (FDTD) simulations is observed. The PCSs sensitivity is linked to the mode intensity distribution. Laing, "Label-free assays on the BIND system," J. Biomol. Screen. 9(6), 481-490 (2004). 9. Y. Nazirizadeh, U. Bog, S. Sekula, T. Mappes, U. Lemmer, and M. Gerken, "Low-cost label-free biosensors using photonic crystals embedded between crossed polarizers," Opt. Express 18(18), 19120-19128 (2010). 10. I. M. White and X. Fan, "On the performance quantification of resonant refractive index sensors," Opt. Express 16(2), 1020-1028 (2008). 11. M. El Beheiry, V. Liu, S. Fan, and O. Levi, "Sensitivity enhancement in photonic crystal slab biosensors," Opt.Express 18(22), 22702-22714 (2010). 12. U. Geyer, J. Hauss, B. Riedel, S. Gleiss, U. Lemmer, and M. Gerken, "Large-scale patterning of indium tin oxide electrodes for guided mode extraction from organic light-emitting diodes," J. Appl. Phys. 104(9), 093111 (2008). 13. L. J. Guo, "Nanoimprint lithography: methods and material requirements," Adv. Mater. 19(4), 495-513 (2007

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Low-cost label-free biosensors using photonic crystals embedded between crossed polarizers

Cited by 70 publications

References 15 publications

Imaging label-free biosensor with microfluidic system

Imaging label-free biosensor with microfluidic system

Photonic crystal slabs for surface contrast enhancement in microscopy of transparent objects

Sensitivity optimization of injection-molded photonic crystal slabs for biosensing applications

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